Functional brain imaging and electrophysiological recording techniques have revolutionized the study of human brain function in cognitive neuroscience research. However, these methods are only able to provide correlational measures between localized neural activity and behavior. They do not themselves establish that any area is necessary for a particular task. Transcranial magnetic stimulation (TMS) is a technique that offers the unique possibility to create a transient virtual lesion by inducing cortical dysfunction in the intact human brain. TMS can disrupt cognitive processing for a few tens of milliseconds with spatial resolution in the order of a centimeter. Thereby, this technique allows the study of functionality of a given brain area in a cognitive process. TMS also has important clinical applications in the treatment of patients with severe depression. It has been shown that TMS improves the mood of some of these patients. Here, we request funds to establish a TMS laboratory at the Center for the Study of Brain, Mind, and Behavior (CSBMB) at Princeton University. We propose to use TMS in conjunction with other functional brain mapping techniques (fMRI and ERPs) that are already established in the laboratory facilities of the CSBMB. The use of TMS will greatly complement the other brain mapping techniques and strengthen the study of human brain function at the Center. A group of 6 scientists will implement the use of TMS into their ongoing research programs. The proposed projects include studies in cognitive neuroscience on the role of prefrontal cortex in cognitive control, on the neural mechanisms underlying conscious visual perception, and on the role of parietal and frontal cortex in visual attention. One project will probe the effects of TMS on hippocampal neurogenesis in an animal model to elucidate the neural basis of the antidepressant action of TMS.